1. Field of the Invention
This invention relates generally to a fastening device for securing panels together.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Ultra high temperature ceramic (UHTC) articles are known to be more brittle and weak than metallic and organic composite articles. The micro-cracked nature of the matrices and/or interfaces within UHTC articles makes it difficult to translate the properties of their reinforcing elements. Structural fasteners have complex loadings with large interlaminar stresses not compatible with monolithic ceramics, and to a slightly lesser extent, composite UHTC's.
One approach to distributing loads in a composite fastener is to form a shank of the fastener by molding threads into a covering formed over a cylindrical core matrix comprising layered axially-oriented carbon or graphite fiber reinforcement. The covering into which the threads are molded includes several layers of carbon fibers drawn onto the core matrix by a helical winding method such that the fibers extend at an angle that is acute relative to the core axis and that preferably corresponds to a pitch angle of the screw threads to be formed into the covering.
Another approach to forming a composite fastener capable of distributing loads is to form its shank by molding threads into an exterior member or casing that includes resin-matrix-embedded axially-oriented material strips wrapped longitudinally over the shank that comprises resin-matrix embedded axially-oriented fibers. A mesh-like overwrap may then be applied over the casing and the threads to introduce off-axis fibers.